Good coffee was to be found in the coffee shops. Each has their own concoction of a variety of components, like sugar, salt, spices, margarine, butter etc. And most coffee roasters imported the Mandeling' Arabica from Sumatra for many years until the Japanese cornered the seeds.
Grown at an altitude of 4,000 to 5,000 feet above sea level its the preferred beans for a good cuppa. It was a lighter shade of black when brewed as coffee-o. Therefore it was named as white coffee. That's the story passed to me by my father.
Well, there was no foreign coffee chains as yet in Malaysia during the 70's. Some have not even existed then. Ipohans were contented with their secret white coffee till the invasion of the trendy and avant-garde.